Self-testing auto monitor ground fault circuit interrupter (GFCI) with power denial

Abstract

A circuit interrupting device including one or more line terminals for connecting to an external power supply, one or more load terminals for connecting to an external load, an interrupting device, a fault detection circuit, and an auto-monitoring circuit. When the auto-monitoring circuit determines that the circuit interrupting device has reached its end-of-life, and it is determined that contacts of said interrupting device have not failed, then a signal is driven to a first level to actuate a switch and open the contacts. Additionally, said signal may further be driven to a second level to inhibit said circuit interrupting device from resetting when it is determined that contacts of said interrupting device have failed.

What is claimed is: 
     
       1. A circuit interrupting device comprising:
 one or more line terminals for connecting to an external power supply; 
 one or more load terminals for connecting to an external load; 
 an interrupting device connected to said line terminals and said load terminals and electrically connecting said line terminals to said load terminals when said circuit interrupting device is in a reset condition and disconnecting said line terminals from said load terminals when said circuit interrupting device is in a tripped condition; 
 a fault detection circuit that detects a fault condition in said circuit interrupting device and generates a fault detection signal when said fault condition is detected, wherein said fault detection signal is provided to said interrupting device to place said circuit interrupting device in said tripped condition; and 
 an auto-monitoring circuit electrically coupled to said fault detection circuit and said interrupting device and continuously monitoring one or more signals to determine an operating state of said circuit interrupting device, wherein at least one of said monitored signals includes said fault detection signal and if said auto-monitoring circuit determines that said circuit interrupting device has reached its end-of-life and it is determined that contacts of said interrupting device have not failed, then a signal is driven to a first level to actuate a switch and open the contacts and then said signal is further driven to a second level to inhibit said circuit interrupting device from being reset by a user, when it is determined that contacts of said interrupting device have failed, the signal is also driven to the second level, wherein the second level has a voltage that is a logic low level. 
 
     
     
       2. The circuit interrupting device claimed in  claim 1 , wherein said auto-monitoring circuit determines whether said contacts have failed by determining if the contacts are stuck together. 
     
     
       3. The circuit interrupting device claimed in  claim 1 , wherein said signal driven to actuate said switch to open the contacts is driven for at least 20 milliseconds. 
     
     
       4. The circuit interrupting device claimed in  claim 1 , further comprising at least one of actuating a visual indicator and actuating an audio indicator. 
     
     
       5. The circuit interrupting device claimed in  claim 4 , wherein said visual indicator includes a light emitting diode (LED). 
     
     
       6. A circuit interrupting device comprising:
 one or more line terminals for connecting to an external power supply; 
 one or more load terminals for connecting to an external load; 
 an interrupter for electrically connecting said line terminals to said load terminals in a reset condition and electrically isolating said line terminals from said load terminals in a tripped condition; and 
 an auto-monitoring circuit configured to automatically perform a self-test routine based on a predetermined schedule and determine whether said circuit interrupting device has reached the end of its useful life, wherein said determination is based at least in part on a result from said self-test routine; 
 wherein, when said auto-monitoring circuit determines that said circuit interrupting device has reached the end of its useful life, a driver signal is driven to a first level for a first length of time to actuate said interrupter to said tripped condition and then further driven to a second level to inhibit said circuit interrupting device from being reset by a user; 
 wherein, when said auto-monitoring circuit determines that contacts of said circuit interrupting device have failed, the driver signal is driven to the second level to inhibit said circuit interrupting device from being reset by a user when it is determined that contacts of said interrupting device have failed, wherein the second level has a voltage that is a logic low level. 
 
     
     
       7. The circuit interrupting device claimed in  claim 6 , wherein said external power supply includes an AC source providing said circuit interrupting device with an AC power signal having a first number of cycles per second and said first length of time is greater than a duration of one of said cycles. 
     
     
       8. The circuit interrupting device claimed in  claim 7 , wherein said AC power signal is a 60 hertz signal having 60 cycles per second and said first length of time is greater than 16.667 milliseconds. 
     
     
       9. The circuit interrupting device claimed in  claim 6 , wherein said auto-monitoring circuit includes a microcontroller having one or more input/output (I/O) ports that can be configured by said auto-monitoring circuit to be either an input or an output, and when said auto-monitoring circuit determines that said circuit interrupting device has reached the end of its useful life at least one of said I/O ports is configured to be an output. 
     
     
       10. The circuit interrupting device claimed in  claim 9 , wherein said driver signal is output on said configured output port. 
     
     
       11. The circuit interrupting device claimed in  claim 10 , wherein said configured output port is changed to an output port from an input port, and said input port is configured to receive analog signals that are converted to digital signals within said microcontroller. 
     
     
       12. The circuit interrupting device claimed in  claim 6 , wherein the driver signal being driven to the second level inhibits said circuit interrupting device from resetting.